[jQuery] Generate and submit file upload form with jQuery

Hi,

I want to collect some input fields that are already present in my
DOM, generate a form with jQuery and submit it. Everything works fine,
unless if one of those input fields is a type="file" field.

$(".trform .sendform").click(function(e) {
    e.preventDefault();
    var form = $(this).closest(".trform");

    var method = form.find(":input[name=method]").val();
    var action = form.find(":input[name=action]").val();
    var enctype = form.find(":input[name=enctype]").val();

    $(document.createElement('form'))
           .attr("method",method)
           .attr("action",action)
           .attr("enctype",enctype);
           .append($(":input",form).clone())
           .submit();
});

If there is a file upload field, it's value after the submit is empty.

Any suggestions what I could do?

Regards, Jan Oliver